// Copyright 2017 Gerasimos Maropoulos, ΓΜ. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package websocket

import (
	"net/http"
	"time"

	"github.com/kataras/iris/context"
)

const (
	// DefaultWebsocketWriteTimeout 0, no timeout
	DefaultWebsocketWriteTimeout = 0
	// DefaultWebsocketReadTimeout 0, no timeout
	DefaultWebsocketReadTimeout = 0
	// DefaultWebsocketPongTimeout 60 * time.Second
	DefaultWebsocketPongTimeout = 60 * time.Second
	// DefaultWebsocketPingPeriod (DefaultPongTimeout * 9) / 10
	DefaultWebsocketPingPeriod = (DefaultWebsocketPongTimeout * 9) / 10
	// DefaultWebsocketMaxMessageSize 1024
	DefaultWebsocketMaxMessageSize = 1024
	// DefaultWebsocketReadBufferSize 4096
	DefaultWebsocketReadBufferSize = 4096
	// DefaultWebsocketWriterBufferSize 4096
	DefaultWebsocketWriterBufferSize = 4096
	// DefaultClientSourcePath "/iris-ws.js"
	DefaultClientSourcePath = "/iris-ws.js"
)

var (
	// DefaultIDGenerator returns the result of 64
	// random combined characters as the id of a new connection.
	// Used when config.IDGenerator is nil
	DefaultIDGenerator = func(context.Context) string { return randomString(64) }
)

// Config the websocket server configuration
// all of these are optional.
type Config struct {
	// Endpoint is the path which the websocket server will listen for clients/connections
	// Default value is empty string, if you don't set it the Websocket server is disabled.
	Endpoint string
	// ClientSourcePath is is the path which the client-side
	// will be auto-served when the server adapted to an Iris station.
	// Default value is "/iris-ws.js"
	ClientSourcePath string
	Error            func(w http.ResponseWriter, r *http.Request, status int, reason error)
	CheckOrigin      func(r *http.Request) bool
	// WriteTimeout time allowed to write a message to the connection.
	// 0 means no timeout.
	// Default value is 0
	WriteTimeout time.Duration
	// ReadTimeout time allowed to read a message from the connection.
	// 0 means no timeout.
	// Default value is 0
	ReadTimeout time.Duration
	// PongTimeout allowed to read the next pong message from the connection.
	// Default value is 60 * time.Second
	PongTimeout time.Duration
	// PingPeriod send ping messages to the connection with this period. Must be less than PongTimeout.
	// Default value is 60 *time.Second
	PingPeriod time.Duration
	// MaxMessageSize max message size allowed from connection.
	// Default value is 1024
	MaxMessageSize int64
	// BinaryMessages set it to true in order to denotes binary data messages instead of utf-8 text
	// compatible if you wanna use the Connection's EmitMessage to send a custom binary data to the client, like a native server-client communication.
	// defaults to false
	BinaryMessages bool
	// ReadBufferSize is the buffer size for the underline reader
	// Default value is 4096
	ReadBufferSize int
	// WriteBufferSize is the buffer size for the underline writer
	// Default value is 4096
	WriteBufferSize int
	// IDGenerator used to create (and later on, set)
	// an ID for each incoming websocket connections (clients).
	// The request is an argument which you can use to generate the ID (from headers for example).
	// If empty then the ID is generated by DefaultIDGenerator: randomString(64)
	IDGenerator func(ctx context.Context) string

	// Subprotocols specifies the server's supported protocols in order of
	// preference. If this field is set, then the Upgrade method negotiates a
	// subprotocol by selecting the first match in this list with a protocol
	// requested by the client.
	Subprotocols []string
}

// Validate validates the configuration
func (c Config) Validate() Config {

	if c.ClientSourcePath == "" {
		c.ClientSourcePath = DefaultClientSourcePath
	}

	// 0 means no timeout.
	if c.WriteTimeout < 0 {
		c.WriteTimeout = DefaultWebsocketWriteTimeout
	}

	if c.ReadTimeout < 0 {
		c.ReadTimeout = DefaultWebsocketReadTimeout
	}

	if c.PongTimeout < 0 {
		c.PongTimeout = DefaultWebsocketPongTimeout
	}

	if c.PingPeriod <= 0 {
		c.PingPeriod = DefaultWebsocketPingPeriod
	}

	if c.MaxMessageSize <= 0 {
		c.MaxMessageSize = DefaultWebsocketMaxMessageSize
	}

	if c.ReadBufferSize <= 0 {
		c.ReadBufferSize = DefaultWebsocketReadBufferSize
	}

	if c.WriteBufferSize <= 0 {
		c.WriteBufferSize = DefaultWebsocketWriterBufferSize
	}

	if c.Error == nil {
		c.Error = func(w http.ResponseWriter, r *http.Request, status int, reason error) {
			//empty
		}
	}

	if c.CheckOrigin == nil {
		c.CheckOrigin = func(r *http.Request) bool {
			// allow all connections by default
			return true
		}
	}

	if c.IDGenerator == nil {
		c.IDGenerator = DefaultIDGenerator
	}

	return c
}
